Apparatus for stripping cables



av. 24', 1970 R. J. WATSON APPARATUS FOR STRIPPING CABLES Filed Jun 25,1968 A s Sheets-Sheet 1 ZNvEA/T Q Nov. 24, 1970 R. J. WATSON 35,541,896

APPARATUS FOR STRIPPING CABLES Filed June 25, 1968 3 sheets-sheet 2 Nov.24, 1970 R. J. WATSON 3,541,896

APPARATUS FOR STRIPPING CABLES 7 Filed June 25', 1 968 s Sheets-Sheet :5

United States Patent 3,541,896 APPARATUS FOR STRIPPING CABLES Richard J.Watson, Danvers, Mass., assignor to Western Electric Company,Incorporated, New York, N.Y., a corporation of New York Filed June 25,1968, Ser. No. 739,673

Int. Cl. H02g l/12 U.S. Cl. 819.51 14 Claims ABSTRACT OF THE DISCLOSUREA cable Stripping apparatus includes a rotating head with first andsecond pivotally mounted cutters. A yoke is moved axially in the head. Afirst cam on the yoke pivots the first cutter to cut through a braidedcable shielding. The shielding disintegrates and exposes a plasticinsulation. A second cam on the yoke then pivots the second cutter,moving a bifurcated cutting blade on the second cutter to cut through anaxially offset portion of the insulation. The second cutter is nextmoved axially. The bifurcated cutting blade strips the severedinsulation axially off of a central conductor core.

BACKGROUND OF THE INVENTION This invention relates to apparatus forstripping coverings off of core members and, more particularly, toapparatus for removing sections of an outer and an inner covering from acentral cable conductor.

In the art of stripping outer and inner coverings off of articles, suchas conventional coaxial cables, it is desirable that simple andreliable, yet effective, semiautomatic and automatic mechanisms beprovided for quickly and easily removing the coverings from a centralcore member, such as a central conductor core. Such mechanisms obviatethe need for time consuming, manual stripping operations, using handtools.

Additionally, it is frequently desired that the outer and innercoverings be stripped from the central core at different points alongtheir respective lengths. In this manner, axially extending sections ofboth the inner covering and the central core may be exposed. The outercovering, moreover, may be formed of braided wires of copper or othermaterial, acting as a shielding for the central conductor core. Therelatively hard nature of such covering will tend to cause injury orexcessive Wear to a cutting blade designed to cut through and strip offa softer inner covering, such as a plastic or other insulation. Both ofthese factors much be taken into account in the design of the apparatus.

SUMMARY OF THE INVENTION An object of the invention resides in new andimproved apparatus for stripping coverings off of core members, such asby removing sections of outer and inner coverings from a centralconductor core of a cable or similar article.

The invention contemplates the provision of a rotatable cutter headassembly having an axially extending opening into which one end of acable is inserted, for example, manually. A pair of cutters or cutterarms are pivoted successively into contact with the cable so that afirst blade may sever and disintegrate a braided outer covering and thena second blade may sever an exposed inner covering surrounding a centralcore member of the cable.

The invention further contemplates the use of a mechanism for displacingthe second blade axially to strip the severed section of the innercovering axially off of the central core, the second blade preferablybeing bifurcated to aid in this stripping operation.

ice

The invention further contemplates the locating of the first and secondblades on the cutters or cutter arms in such positions that the outerand inner coverings are severed at axially spaced locations along thelength of the cable.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 through 5 are side elevationalviews of portions of a rotating cutter head assembly constructed inaccordance with the principles of the invention, illustrating successivestages in the operation of various elements of the head during thestripping of a pair of concentric coverings off of a central conductorcore of a coaxial cable;

FIG. 6 is an exploded isometric view of a major portion of the cutterhead assembly showing additional elements thereof;

FIGS. 7 and 8 are fluid circuit diagrams illustrating successive stagesin an operating and control system which may be utilized with the cutterhead assembly of the FIGS. 1-6; and

FIG. 9 is a side elevational view of a portion of a co axial cableshowing the cable after the stripping of sections of braided outercovering and an inner covering off of a central conductor core by meansof the apparatus of FIGS. 1-8.

DETAILED DESCRIPTION Turning first to FIG. 9 of the drawing, a coaxialcable 11 includes an axially extending central conductor core 12surrounded by a layer of plastic or other insulation 13, for example, aplastic sold under the trade name Teflon. The insulation covering 13 is,in turn, surrounded by an outer shielding member, such as covering ofbraided copper wires 14. It is desired that the cable 11 be stripped toexpose an axially extending portion 12 of the central conductor core 12and an axially extending portion 13' of the inner covering of insulation13, as is shown in FIG. 9.

Referring next to FIGS. 1-6, an apparatus for stripping an article, suchas the coaxial cable 11, to provide the configuration of FIG. 9 includesa cutter head assembly 16 which is mounted to rotate with rotation of anaxially movable shaft 17. The cutter head assembly 16 comprises allelements depicted in FIGS. 16 with the exception of the cable 11 and achuck 33. Suitable bearings (not shown) mount the shaft 17 for bothrotation and axial movement. Included in the cutter head are a pair ofpivotally mounted cutter arms 18 and 19 and a yoke 21. The yoke 21 isfixed to the shaft 17 by a dowel pin 20. The cutter arms 18 and 19 aresecured to pivot pins 22 and 23, respectively. The pivot pins extendthrough a pair of mounting holes in each of a pair of plates 24 and 25(FIG. 6) which are rotatable with rotation of the shaft 17. Two sets ofcounterbalance members 26 and 27 (only one of which sets is shown inFIG. 6) are carried on opposite ends of the pivot pins 22 and 23 tocounterbalance the pivotally movable cutter arms 18 and 19,respectively, during rotation of the cutter head assembly 16. A pair ofcutter blades 28 and 29 are carried by the pivotally mounted cutter arms18 and 19, respectively. Each blade extends at a right angle to a majorportion of the respective cutter arm 18 or 19. The two blades 28 and 29extend facing generally toward one another, being slightly axiallyoffset from one another, at opposite sides of a central axis of thecutter head assembly 16. The cutter head assembly includes an axiallyextending opening 31 (FIGS. 1 and 5) into which a coaxial cable 11 maybe thrust axially, for example, manually. A stop 32 extends into theopening 31 to locate accurately an end of the cable 11. The stop may bemounted on the plate 24 (FIG. 6) for adjustable movement, for example,ax-

ially. A chuck 33 is located to grip the cable 11, holding the cableaxially against the stop 32 during the stripping operation to beperformed by the cutter head assembly.

Each of the pivotally mounted cutter arms 18 and 19 has a cam followersurface 36 or 37 located along a portion thereof facing away from thecentral axis of the cutter head assembly 16. The yoke 21 has a pair ofcamming projections 38 and 39 located along opposing portions thereoffacing toward the central axis of the assembly. The camming projection38 will contact the cam follower surface 36 on the cutter arm 18 as theyoke 21 is moved axially to the left (as seen in FIG. 2). The cammingprojection 39 will then contact the cam follower surface 37 on thecutter arm 19 as the yoke 21 is moved further to the left (FIG. 3).

As may be seen in FIGS. 1-3, this arrangement will cause first the blade28 and thereafter the blade 29 to pivot into cutting engagement with thecoaxial cable 11. The first blade 28 will cut through the braided outercovering 14 (FIG. 9) as the cutter head assembly 16 is rotated about itsaxis and, therefore, the pivoted cutter arm 18 orbits the cable 11. Thesevering of the braided covering 14 will cause the braided covering todisintegrate as the blade 28 sweeps about an outer surface of the innercovering 13. A blow pipe 40 (FIGS. 7 and 8) may be positioned adjacentthe cutter head assembly to direct pressurized air at the severedbraiding so as to aid in causing the braiding to disintegrate. Once thebraiding has been removed, a bifurcated portion 41 (FIG. 6) of thesecond blade 29 will contact the relatively soft inner layer ofinsulation 13 (FIG. 9), severing the insulation as the blade 29 orbitsthe central conductor core 12. The second blade 29 is offset axially bya slight amount from the first blade 28, as may be seen in FIGS. l-6, inorder to produce the configuration shown in FIG. 9 which requiresaxially spaced cuts for the two different layers 13 and 14. The axialoffset between the blades 28 and 29 will result in the formation of theexposed, axially extending, central conductor core and insulationportions 12' and 13', respectively. The cutter blades 28 and 29 may besimply removed and replaced in the cutter head assembly by removal offour dowels 42 which retain the blades in receiving portions of therespective cutter arms 18 and 19. This will enable an operator tosubstitute different cutter arms 18 and/or 19 for those shown. Therelative degree of axial olfset between the blades 28 and 29, and,therefore, the lengths of the exposed portions 12' and 13' may be easilyand quickly readjusted to suit new requirements. The offset may, ofcourse, be reduced to zero to expose an axially extending portion 12' ofthe central conductor core 12 only, if such is desired.

The plates 24 and 25 (FIG. 6) are secured to a generally U-shaped guidemember 43. The crosspiece 44 and the legs 46 and 47 of this guide memberbound a channel 48 aligned with the axially extending opening 31 (FIGS.1 and for receiving the cable 11. The channel 48 constitutes a guidewayfor the above-described axial movement of the yoke 21. A guidingfunction is also performed by the dowel pin associated with the yoke 21,thedowel pin following slots 51 (FIG. 6) in the plates 24 and 25, aswell as by the plates 24 and themselves. A pair of coil springs 53, 53(FIGS. 1-5), having first ends thereof held against an axially fixedbearing 54, have their second ends bearing against the cross-piece 44 tobias the guide member 43 toward the right (as seen in FIGS. 1-3). Thus,the guide member 43 is held in a normal rest position during the initialaxial movement of the loke 21 which causes the cutting operations of thecutter blades 28 and 29 (FIGS. 1-3). However, once the yoke 21 has beenmoved axially, sufficiently far to engage the cross-piece 44 of theguide member, which circumstance will occur after the second blade 29has cut completely through the inner covering 13 (FIG. 3), continuedaxial displacement of the yoke 21 will move the guide member 43 to theleft (as seen in FIG.

4). As stated above, the cutter arm 19 is secured to the pivot pin 23,which is pivotally mounted on the plates 24 and 25. The plates 24 and 25move axially with the guide member 43. Thus, the bifurcated portion 41of the second blade 29 will strip the severed section of the innercovering 13 axially ofi of the central conductor core 12 of the cable 11as the second cutter 19 moves axially to the left.

The operation of the apparatus will next be described, with furtherreference to FIGS. 7 and 8 of the drawing, wherein an exemplary fluidcircuit for operating and controlling the cutter head assembly 16 in themanner described above is illustrated. The operating medium ispreferably a pressurized fluid, typically compressed air, as describedhereinafter. Alternatively, however, a fluid at subatmospheric pressuremay be utilized with a suitably modified fluid circuit or an analogouselectrical control circuit may be substituted in a manner obvious to aperson having ordinary skill in the art.

An air compressor or pump 56 is connected both to the blow pipe 40 andto a main control valve 57. The two operating positions of the valve 57are shown in FIGS. 7 and 8, respectively. FIG. 7 shows the condition ofthe fluid circuit during axial loading of the coaxial cable 11 betweenthe jaws of the initially-open chuck 33 (see also FIG. 5) and againstthe stop 32 in the opening 31 of the cutter head assembly 16. FIG. 8shows the condition the fluid circuit will assume after the coaxialcable has been correctly positioned in the opening 31 for cutting andstripping by the cutter head assembly. The main control valve 57 may beoperated manually or may be actuated by any known mechanism forsignalling the correct positioning of the coaxial cable against the stop32, for example, a solenoid energized upon the closing of a suitablypositioned limit switch.

In the initial, loading condition of the circuit shown in FIG. 7,pressurized air is communicated by the main control valve 57 from thecompressor 56 to a first (right) end of a main cylinder 58 whichcontains a piston (not shown). A piston rod 59 controls the axialpositioning both of the shaft 17 for moving the yoke 21 axially and of areversing valve 61. The reversing valve 61 is initially positioned tocommunicate pressurized air from the compressor 56 to a first (lower)end of a chuck control cylinder 62 so as to hold open the jaws of thechuck 33. The main control valve 57, when in the loading position (FIG.7), also communicates with exhaust the opposite second ends of thecylinders 58 and 62, as well as the conventional, fluid-operatedmechanism for engaging a clutch 63. The clutch 63, when engaged bycommunication with pressurized air from the compressor 56, will connectthe shaft 17 to rotate with a rotary drive shaft (not shown).

The coaxial cable 11 is now loaded, for example, manually, such that thecable extends between the open jaws of the chuck 33 (FIG. 5), while oneend of the cable contacts the stop 32, as shown in FIG. 1. The maincontrol valve 57 is then moved, for example, manually by means of ahandle 64, into the position shown in FIG. 8. As a result, pressurizedair is applied to the second ends of both the main cylinder 58 and thechuck control cylinder 62, as well as to the clutch 63. At the sametime, the first (right) end of the main cylinder 58 is communicated toexhaust. Thus, the piston rod 59, extending from the main cylinder '58,begins to move to the right (as seen in FIG. 8). A cam 66 and a spring67 cooperate, upon an initial rightward movement of the piston rod 59,to reposition the reversing valve 61 into the FIG. 8 position of thisvalve. The first (bottom) end of the chuck control cylinder 62 iscommunicated to exhaust upon this movement of the reversing valve 61.Thus, the jaws of the chuck 33 close about the coaxial cable 11,gripping the cable to hold it firmly in place driving the subsequentcutting and stripping operations. This is the condition of the apparatusshown in FIG. 1.

The main control valve 57 also functions to cause engagement of theclutch 63 for rotating the shaft 17 so as to rotate the entire cutterhead assembly 16. A flow control valve 68 is positioned in a line 69leading to the clutch 63. The flow control valve 68 is preferablyadjusted to cause engagement of the clutch 63, initiating rotation ofthe shaft 17 (FIG. 1), after the chuck control cylinder.62 has closedthe jaws of the chuck 33 about the coaxial cable 11 to grip the cabletherebetween.

As the piston rod 59 moves to the right (as seen in FIG. 8), a rockerarm 71 and collet 72 cooperate to displace the rotating, axially movableshaft 17 and the associated yoke 21 to the left (as seen in FIG. 8 andin FIGS. 1-4). 'Suflicient leftward movement of the yoke 21 to pivot thefirst cutter arm 18 into cutting engagement with the outer layer ofbraided shielding 14 is to occur only after (1) the chuck 33 has firmlygripped the cable 11 and (2) the clutch 63 has been engaged to startrotation of the shaft 17 and, therefore, the cutter head assembly 16. Aflow control valve 73 in a line 74 leading into the second (left) end ofthe main cylinder 58 may be adjusted to control the rate of displacementof the piston rod 59 and, therefore, of the axially movable shaft 17.

As the shaft 17 and the yoke 21 are displaced to the left (as seen inFIG. .2), the first cutter arm 18 is pivoted by the camming action ofthe first camming projection 38 against the cam surface 36. Thus, thefirst cutting blade 28 engages the braided outer covering 14. The blade28 orbits the inner covering 13, severing the braided covering 14 whichdisintegrates as the blade 28 moves. The disintegration of the braid isaided by the influence of the stream of pressurized air issuing from theblow pipe 40 (FIG. 8).

Continued movement of the yoke 21 to the left (as seen in FIG. 3) causesthe bifurcated portion 41 (FIG. 6) of the second cutter blade 29 toengage an axially offset portion of the exposed, relatively soft innercovering 13. The insulation covering 13 is now severed without anysignificant wear or damage to the bifurcated portion of the blade.

Further leftward movement of the yoke 21 (as seen in FIG. 4) will drivethe guide member 43 to the left, moving the plates 24 and 25 and thecutter arms 18 and 19 also to the left. Movement of the bifurcatedportion 41 of the second cutting blade 29 to the left will strip thesevered section of the inner covering 13 axially off of the centralconductor core 12 of the coaxial cable 11. As set forth above, the cableis retained against axial movement during the stripping action of theblade 29 by means of the chuck 33.

The resultant configuration of the stripped coaxial cable 11 is depictedin FIG. 9. It should be noted, once again, that the section of the innercovering 13' cut and stripped by the second cutter blade 29, exposingthe conductor core at 12, is offset axially from the section of theouter covering 14 cut by the first cutter blade 28, exposing theinsulation at 13', due to the axial offseting of the two blades asdescribed above. Additionally, it should be clear that the braidedcopper wires of the outer covering 14 will not have caused any damage orexcessive ware to the bifurcated portion 41 of the second cutting blade29, all contact between the covering 14 and the blade 29 having beenavoided.

The main control valve 57 may now be returned to the position shown inFIG. 7, for example, due to the bias of a return spring (not shown)effective upon release of the handle 64. The fluid circuit, thus,reassumes the initial loading condition of FIG. 7, while the cutter headassembly 16 returns to the operating position shown in FIG. 1. Thestripped coaxial cable 11 may now be removed from between the openedjaws (still as in FIG. of the chuck 33 and the apparatus may be used instripping additional sections of cable.

It is to be understood that the above described apparatus is simplyillustrative of one embodiment of the invention. Many modifications maybe made without departing from the invention.

I claim:

1. In a severing device for making successive cuts in a held article;

a pair of cutter means separately mounted for pivotal movement intoengagement with said article and for rotary movement about said article;

means for rotating said cutter means about the article; and

means operable while the cutter means are rotating for successivelypivoting a first of said cutter means into severing engagement with saidarticle, and then for pivoting the other of said cutter means intoservering engagement with said article to make a cut at a depth greaterthan the cut depth of said first cutter means.

2. In a severing device as defined in claim 1, wherein the pair ofcutter means include a pair of cutter blades which are axially spacedfrom each other along the axis of rotation of said cutter means aboutthe article.

3. In a severing device as defined in claim 1, wherein one of saidcutter means is mounted for axial movement to strip a cut portionaxially off of said article and includes a bifurcated blade forstripping the cut portion.

4. In a cutting device for cutting different sections of an article;

a pair of cutters mounted for pivotal movement toward an articlepositioned between the cutters, said cutters having blades offset fromeach other to engage dilferent sections of the article;

means for imparting relative rotational movement between said articleand said cutters; and

means operated during said relative rotation for pivoting a first ofsaid cutters to move its blade into engagement with said article to makea cut at a first depth and then pivoting the second cutter to move itsblade into engagement with said article to make a cut at a second depthgreater than said first depth.

5. In a cutting device as defined in claim 4;

means mounting the second cutter for movement along the axis of relativerotation between said article and said cutters; and

means operative while the second cutter is in engagement with thearticle for axially moving said second cutter.

6. In a device for stripping a cable comprising a pair of concentriccoverings on a core wire;

a head having an axial opening therein;

a pair of oppositely disposed cutter arms pivotally mounted in the headand extending into said opening, each of said cutter arms including ablade;

means for positioning an end section of a cable within said opening toposition the coverings in alignment with said blades;

trneans for rotating said head relative to said cable to rotate saidblades about said cable; and

means for sequentially pivoting a first of said cutter arms to move afirst blade to penetrate and sever a first covering, and then pivotingthe second of said cutter arms to move the second blade to penetrate andsever the second covering.

7. In a device as set forth in claim 6;

means rendered effective following pivoting of the second cutter arm formoving said second cutter arm axially of said head to strip the secondcovering from the core wire.

8. In a device as set forth in claim 6;

said blades on said cutter arms being offset axially one from the otherin position to sever axially spaced sections of the first and secondcoverings.

9. In apparatus for stripping a pair of concentric coverings off of anaxially extending core, the outer covering of the pair having a braidedconfiguration;

a rotatable head having an axially extending opening for housing thecovered core;

7 a pair of cutters mounted in said head to pivot into cuttingengagement with the concentric coverings of the core in said opening;means for rotating said head to orbit said cutters about the coveredcore; means for pivoting a first of said pair of cutters into cuttingengagement with the braided outer covering to sever and disintegrate thebraided covering with rotation of said head, whereby an inner coveringof the pair of concentric coverings is exposed; and means operatedsubsequent to pivoting said first pair of cutters for pivoting thesecond pair of cutters into cutting engagement with the exposed innercovering to sever the inner covering. 10. In apparatus for stripping apair of coverings off of a core, as set forth in claim 9;

said first cutter including a pivotally mounted arm carrying a firstblade positioned to engage a first location on the outer covering duringrotation of said head for severing and disintegrating the outercovering; and said second cutter including a pivotally mounted armcarrying a second blade positioned to engage a second location on theexposed inner covering during continued rotation of said head with theouter covering disintegrated, said second location on the inner coveringbeing offset axially from said first location on the outer covering. 11.In apparatus for stripping a pair of coverings off of a core, as setforth in claim 9;

means rendered effective upon said second cutter pivoting to sever theexposed inner covering for moving said second cutter axially along thecore to strip the severed inner covering off of the core. 12. Inapparatus for stripping a pair of coverings off of a core, as set forthin claim 11;

said second cutter including a pivotally mounted arm carrying abifurcated cutter blade having a recess between the bifurcationspositioned to engage the inner covering and strip the inner covering offof 8 v l the core upon axial movement of said second cutter.

13. In apparatus for stripping a pair of coverings 01f of a core, as setforth in claim 9, said first and second pivoting means comprising:

a first cam follower surface located on said first cutter;

a second cam follower surface located on said second cutter;

a yoke mounted for axial movement in said head;

a first camming projection mounted on said yoke in position to engagesaid first cam follower surface and pivot said first cutter into cuttingengagement with the outer braided covering upon axial movement of saidyoke;

a second camming projection mounted on said yoke in position to engagesaid second cam follower surface and pivot said second cutter intocutting engagement with the exposed inner covering upon further axialmovement of said yoke; and

means for moving said yoke axially of the covered core.

14. In apparatus for stripping a pair of coverings off of a core, as setforth in claim 13;

means mounting said second cutter in said head and positioned to beengaged by said yoke upon continued axial movement of said yoke afterpivoting of said second cutter into cutting engagement with the exposedinner covering for moving said second cutter axially with continuingaxial movement of said yoke to strip the severed inner covering off ofthe core.

References Cited UNITED STATES PATENTS 2,526,955 10/1950 Kugler 30-942,695,537 11/1954 Imman et al. 3091.2 3,222,957 12/1965 Kramer et al.819.51 3,309,768 3/1967 Thompson 309l.1

ROBERT C. RIORDON, Primary Examiner 40 R. V. PARKER, JR., PrimaryExaminer

